Environmental Factors Influence the Seed Phenotypic Variation of Sapindus mukorossi Gaertn. and Sapindus delavayi (Franch.) Radlk. in China

Abstract

Abstract The phenotypes of Sapindus are significantly influenced by environmental factors, but the responses of oil-related seed phenotypes to environmental factors are still unclear. We sampled 115 seed accessions of Sapindus mukorossi Gaertn. and 33 of Sapindus delavayi (Franch.) Radlk. from fifty-six distinct locations in China to explore the effects of environmental factors on the seed phenotypes. Pearson’s correlation analysis showed that 100-seed kernel weight (SKW), 100-seed shell weight (SSW), and seed kernel content (SKC) were the phenotypes most sensitive to the environmental influence (significantly associated with at least ten environmental factors). Redundancy analysis explained 26.13% of the variance and revealed that longitude was negatively correlated with SKW and SKC but was positively correlated with SSW, whereas elevation had the opposite effect. Monthly sunshine hours was negatively correlated with 100-seed weight and SSW. Additionally, the Mantel test showed that the seed phenotypic variations in Sapindus mukorossi and Sapindus delavayi were significantly affected by environmental factors differently. SKW and SKC of Sapindus delavayi were more sensitive to the influence of key environmental factors and therefore had more potential for oil development. It is recommended to cultivate Sapindus delavayi at lower longitudes to facilitate seed kernel development and promote oil yield.